Method for making intricate hollow powder metal parts



Spt- 24, 1957 M. s. RoUsH 2,807,437

METHOD F OR MAKING INTRICATE HOLLOW POWDER METAL PARTS Filed May l, 1952 vFJ :ii

4 mws- JPII METHOD FOR MAKING INTRICATE HOLLOW POWDER METAL PARTS Milton S. Roush, Painesville, Ohio, assigner to Thompson Products, Inc., Cleveland, Ohio, a corporation of Ohio Application May 1, 1952, Serial No. `285,464

9 Claims. (Cl. 253-77) The present invention is concerned with the manufacture of uid directing members from powdered metal, particularly iiuid directing members for use in jet engines.

The present invention is particularly applicable to the manufacture of hollow fluid directing members such as inlet guide vanes, rotor blades and stator vanes of jet turbine engines and involves forming powdered metal compacts into segmental sections of the finished member, the interior of each of the segmental sections being suitably recessed to dene the particular shape desired in the hollow section of the finished article when the segmental sections are assembled. Upon assembly of the sections, the segments are joined into an integral fluid directing member by infiltration of the powdered metal sections with a suitable in'filtrant metal.

An object of the present invention is to provide an improved method of making intricate, hollow powder metal parts.

Another object of the present invention is to provide an improved method for assembling porous metal compacts, and joining the compacts together by a process of infiltration with metal.

Another object of the present invention is to provide an improved hollow iiuicl directing member composed of powdered metal segmental sections.

Another object of the present inventioriis to provide an improved fluid directing member in which selected areas of the member are provided with different porosities.

Still another object of the present invention is to provide a fluid directing member composed of segmental sections, cach consisting of a powdered metal' compact, the sections upon assembly defining a` hollow interior and having cooling slots communicating the hollow interiorof the fluid directing member with the surface of the member.

ln making the huid directing members of the present invention, powdered metal, such as powdered iron or a powdered heat resistant alloy composition is molded into a piurality of segmental sections which upon assembly define the shape ofthe ultimate fluid directing member. The segmental compacts are then sintered and coined prior to assembly. Upon assembly of the two segmental portions, the assembled `compacts are bondedtogether by means of infiltration with a metal infiltrant network, thereby bonding` together the porous metal skeletons of the segmental sections.

One of the advantages of using the above described method resides in the fact that the segmental sections are coined separately so that, if desired, each of the sections may be selectively coined to produce areas of differing density and porosity within the `same section. For example, inthe case of guide vanes, the portions of the segmental sections defining the leadingA and trailing edges of the vane may be coined to leave these areas with a porosity greater than the porosity of the central portion of the vane.

The control of porosity inherent in the presently de- Patented Sept. 24, 19517 scribed processes is very useful in the manufacture of inlet guide vanes, where a uid is bled through the vanes for de-icing purposes, and for the manufacture of nozzle vanes where a liquid coolant is bled through the porous portions of the vane for evaporative cooling.

A further description of the present invention will be made in connection with the attached sheets of drawings which illustrate four types of fluid directing members produced according to the present invention. p

In the drawings:

`Figure 1 is afragmentary view in perspective of two segmental powdered metal compacts used in the manufacture of an inlet guide vane, the two segments being shown prior to assembly thereof; i

Figure 2 is a cross-sectional view of the `inlet guide vane of Figure l, with the segments thereof in assembled relation after infiltration;

Figure 3 is a fragmentary View in perspective of a modified form of the invention in which each of the segmental sections is provided with longitudinally extending ribs; Y

Figure 4 is a cross-sectional view of the fluid directing member of Figure 3, with the segments thereof in assembled relation after infiltration;

Figure 5 is a fragmentary view in perspective of still another modified form of the invention in which separate ribs are provided within the hollow interior of the vane;

Figure 6 is a cross-sectional view of the liuid directing member of Figure 5, after assembly and infiltration;

Figure 7 is a fragmentary view in perspective of another modiiied form of the present invention in which cooling slots are provided to communicate the hollow interior of the vane with the surface of the vanes; and

Figure 8 is a cross-sectional view taken substantially along the lines ViIl--VIII of Figure 7.

As shown inthe drawings:

Reference numerals 10 and 11 indicate generally two compacted metal hollow sections molded by conventional powder metallurgy techniques.- Section 1t) is generally of a convex configuration externally, while section 11 is generally concaveexternally, the two sections 10 and 11 upon assembly defining an arcuately shaped hollow fluid directing vane. Convex section 10 includes a longitudinally extending thickened marginal portion 12 having a flattened inner face, a recessed arcuate longitudinally intermediate portion 13, and a relatively flat faced longitudinally extending opposite marginal portion 14, while the concave section 11 includes a similar inner relatively dat longitudinally extending marginal portion 16, agenerally arcuate recessed intermediate longitudinal portion 17, and an inner relatively flat longitudinally extending opposite marginal portion 18. In order to locate the sections 10 and 11 in proper alignment, the longitudinaily extending marginal portions 12 and 14 of the section 1) may be provided with spaced conical locating pins or bosses 20 (Figure 2) which are received within complementary conically shaped recesses 21 provided in the longitudinally extending marginal portions 16 and 18 of section 11. f

The sections 10 and 11 may be composed of any suitable metal su-ch as iron, where the fluid directing member is to be used under relatively low operating temperatures, or maybe composed of heat resisting alloys where the parts are to be employed in the hot zone of a jet engine. In a preferred embodiment of the present invention, the metal particles making up the sections 16 and 11 are separately molded, and sintered in a protective atmosphere of hydrogen, or the like, at a sintering temperature appropriate lto the metal used. After sintering, the'sinteredcompacts are then coined into nal shape prior to assembly. In a preferred embodiment of the invention, the sections are selectively coined to make portions of the section more porous than other areas of the same section.

Y itour of the vane.

the vane structure of Figure '1, it is preferable to make the areas of thef sections adjacent to the leading and trail- :dngedgewmoreporousgthan the central portionof the vane afuflreujx; :if fi Y i After-. coihing-theompactedmetal sections 10 and y11 ,are assembled `together with the locating fpinslreceived then clamped together: e Therpowderedmetal sections'ar'e "joined-.tinto `an.integralmember.by infiltrating the sections about .their :areas of .contact with anV iniltrant metal. Forlowvtemprature work, copper and copper base alloys For example, in s within the recesses `21,-and 4the sections 10 landnll are form asuitable iniiltrant `for ferrous metal compacts, while for viluid:directing members `intended forvery high itemperatrefworh heat and oxidation-resistant alloys will be .indicated for .the .inltrant In infiltrating the assembled-compacts, a rod of solid,Y

e .The f orm of the invention illustrated in Figures 5 and 6 1s similar to that shown in Figures 3 and 4 except that preshaped individual ribs are employed in place of the in- `tegral ribs of the previous form. In this form of the invention, the convex upper section 30 as well as the concave lower section 31 are ,provided with longitudinally extending grooves, the grooves or notches in the upper section r30 being -identiiied at numeral 45, and those inxthe lower section 3`1'beingidentiiied at numeral 46. Upon assembly of the sections 30 and V31, the groovesor notches 45 and 46 are vertically aligned to receive a paire-of elongated, rectangularribs 48 therein. Theribs 48 Vare prefe ably composed of a powdered metal compact of the type employed in the body of the .sections'30 and 3K1; The inltration of the /ass'embled'sections withy the ribs in place is carried out in the manner described for the previous forms of the invention.

` The modiiedform of the invention illustrated in Figures vmaintained, at 4a temperature above the melting pointof the 1 inliltrant metal, and retained therein for a time sufficient 1to permit diffusion of the molten inltrant metal through the'in'ter-lparticle voids in the powdered metal sections. After coolingl and upon solidiication of the inltrant metal, Ythe porous metal sections are joined together by means of anetwork of the iniltrant meta-l. Since the leading and trailing :edge face portions Iof the assembled compacts are moreporous than the central portion due to selective coming, there will 'be-a greater quantity of inltrant metal per unit area at these -leading and trailing edge portions 'than' atthe'portions intermediate the ends. This diierence in'finiltrant concentration has been ind-icated by heavier Vstipplingin the drawings in the areas of greater iniiltrant concentration. Further heat treatment of the inltered v compact to improve the physical characteristics of the compact may then be carried outaccording to the process described inrGoetzel Patent No. 2,456,779 issued Decemlber .21, 1948.

' 'The `modiied -form of the invention illustrated inV Figlures 3. and 4 provideslongitudinally extending ribs through Y the'hollovvcentral portion of the vane. As seen in these jdrawings, thercomposite vane is built up from a pair of powdered metal sections, comprising a convex shaped upperisection 30 and a concave shaped lower section 31.

s The lateral width of the upper section 30 is less than the fa-lignment of the `sections 30 and 31 dene afgenerally hollow interior.` The upper section 30 is provided with a pair of spaced longitudinally extending ribs 40 andr41 tion 31 upon assembly of the two sections to provide longi- `Etudinallyextending ribs intermediate 'the edges of the Nane `which divide the hollow interior of the vane into three spaced hollow compartments.

Iniiltration of the assembled sections 30 and 31 can be accomplished in the same manner a-s thatdescri-bed for -thefform of the invention illustrated in Figures 1 and 2. In addition to supplying inltrant metal along the abutting `faces'134, 236,35 and` 37 additional amounts .of inltrant The sections 30 and 31 have recessed l intermediate-portions 38 and 39 respectively which upon Y which Vabut correspondingly located ribs V42 and 43 in secr vmetal can beapplied centrally of the .vane along thetribs between 40;:41,1421and 43to provide additional bonding themsscmbledsections.- s

7 and 8 of the drawings is applicable toany of the previouslydescribed modifications. `In this form ofthe invention, an uppersection 5t) composed of'a powdered metal compact,V and a lower section 51,of similar composition 'are `assembled Vtogether in'face contact along a yparting 'line SZ.V The internal ,recesses inthe sections 50 and 51 define an `internal cavity 54. Each of the sections 50 and 51 is coinedprior t-o assembly to provide laterally extending complementary'notc'hes in the mating face of each section which, upon assembly of the two components', dene spaced. cooling slots V56 which communicate the hollow cavity 54 with the surface of the .iinished vane. lIt will `b'e .appreciated that these cooling slots maybe placed 'in both the leading and trailing edges of the vanes or blades, Vand that the provision of these laterally extendingV slots ,provide for more eicient cooling of the fluid directing member. Since `the slots 56 are of substantial width compared to the `vsize of the pores of the mating sections '50 .and 51, inliltration of the assembled sections with the iniiltrantrmetal does not Vlill up the slots.

' It will jbe appreciated that modications and variations may be eected without departing from the scope of the novel concepts of the present invention. l i vI claim a's my invention:v Y Y Y Y 1. The method of making hollow powdered metal parts which `comprises shaping a pair of powdered metal compacts into aV pair-of. sections each having Vlongitudinally extending marginal portions andan intermediately re'-V cessed portion between said marginal portions, coining said sections-to provide the marginal portions thereof withV a greater porosity thanV the intermediate portions thereof, assembling said pair of sections together with the longitudinally extending marginal portions of one of vsaid pair of sections abutting the longitudinally extending marginal portions of the other of said sections, with the` recessed portions of both of said sections cooperating to form a hollow central portion between the abutting portions, and inltrating the assembled sections with an in- Y ltrant metal along thesgreater porosity abutting portions to bond said abutting portions together.

2. The method of making'hollow'powdered metal parts which comprises molding powdered`metal compacts Ainto a krpair 'of sections each having vlongitudinally extending face portions and .an intermediate recessed portion between saidface portions, sintering said sections, selectively coining said sections to produce a pair of porous sections each having longitudinally vextending face portions and an intermediate recessed portion between said face portions, saidlongitudinally extending face portions having -a higher degree of porosity than said intermediate recessed.portion, assembling said pair of sections together with the longitudinally extending face portions of one of said pairof sections abutting the longitudinally extending face portions'ofthe other of said sections, with the intermediate `recessed'portions of both ofk said sections cooperating to form a hollow central portion between the aautringrfae pQrtiQns,.-amrininaiing the assasblsflewtions with an intiltrant metal along the relatively higher degree of porosity abutting face portions to bond said abutting face portions together.

3. A hollow fluid directing member comprising a pair of porous compacted powdered metal sections, said sections each including leading and trailing edge portions in face Contact, with a recessed portion delining a substantially hollow portion included between the leading and trailing edge portion, said sections being joined together with an inliltrant metal and having a greater quantity of the inltrant metal per unit area at the leading and trailing edge portions than at the portions of said member between said leading and trailing edge portions.

4. A hollow uid directing member comprising a pair of porous compacted metal sections each having longitudinally extending face portions and a recessed intermediate portion extending therebetween, saidsections being joined together with said longitudinally extending face portions in abutting contact, and said intermediate recessed portions cooperating to define a substantially hollow interior between said face portions, said sections being joined together with an inliltrant metal and having a greater quantity of iniiltrant metal per unit area at the face portions than in said intermediate portions.

5. A hollow uid directing member comprising a pair of porous compacted metal sections each having longitudinally extending face portions and an intermediate recessed central portion extending therebetween, said face portions having a greater porosity than said recessed portions, said sections being joined together with said longitudinally extending face portions in abutting contact and said recessed portions cooperating to dene a generally hollow interior between said face portions, said sections being joined together with an inltrant metal and having a greater quantity of infiltrant metal per unit area at the face portion than in said intermediate portions.

6. A hollow uid directing member comprising a pair of porous compacted metal sections each having a pair of spaced longitudinally extending face portions and a recessed intermediate portion therebetween, one of said pair of sections having protuberances extending from itslongitudinally extending face portion, the other of said pair of sections having apertures therein receiving said protuberances to position said sections in alignment with each other with the longitudinally extending face portions on the other of said sections, the recessed portion of each of said sections when in assembled position cooperating to dene a substantially hollow interior, and an iniiltrant metal network joining said sections together along the abutting longitudinally extending face portions of said sections and having a greater quantity of the inltrant metal per unit area at the longitudinally extending face portions than in said intermediate portions.

7. A hollow fluid directing member comprising a. pair of porous compacted metal sections each having a pair of spaced longitudinally extending face portions and a recessed intermediate portion therebetween, each of said sections having longitudinally extending ribs disposed between said longitudinally extending face portions, said sections being joined together with the longitudinally extending face portions and the ribs of one of said sections being in abutting contact with the longitudinally extending face portions and ribs of the other of said sections, the recessed portion of each of said sections when in assembled position cooperating to dene a substantially hollow interior, and an intiltrant metal network joining together the abutting longitudinally extending face portions of said sections and having a greater quantity of the intiltrant metal per unit area at the longitudinally extending face portion than in said intermediate portions.

8. A hollow fluid directing member comprising a pair of porous compacted metal sections each having a pair of spaced longitudinally extending face portions and a recessed intermediate portion therebetween, said sections being assembled with the longitudinally extending face portion of said sections in face to face contact, each of said sections having at least one longitudinally extending notch between the longitudinally extending face portions thereof in alignment with a notch on the other ot said sections, a rib received within `the aligned notches, the recessed portions of said sections when in assembled position cooperating to dene a substantially hollow interior, and an inltrant metal network bonding the longitudinally extending face portions of said sections together and having a greater quantity of the inliltrant metal per unit area at the longitudinally extending face portions of said sections than in said intermediate portions.

9. A fluid flow directing member comprising a pair of porous powdered metal compacts defining an arcuate ilu-id directing vane, said compacts being separated iu an intermediate portion thereof to provide a substantially hollow, longitudinally extending interior, both of saidv sections being slotted transversely of said vane to provide a plurality of open-ended slots communicating said hollow interior with the surface of said vane, said compacts being joined together along areas beyond said hollow interior with an intltrant metal network and having a greater quantity of the inltrant metal at said areas than in said intermediate portions.

References Cited in the le of this patent UNITED STATES PATENTS 994,166 Kienast June 6, 1911 2,341,860 Ellis Feb. l5, 1944 2,401,483 Hensel `lune 4, 1946 2,514,525 Stulen July 11, 1950 FOREIGN PATENTS 611,650 Great Britain Nov. 2, 1948 629,326 Great Britain Sept. 16, 1949 878,999 France Nov. 2, 1942 OTHER REFERENCES Iron Age: February 23, 1950, pages 74-77 incl. Seven Ways To Produce Turbine Bladesfpub. in SAE Journal, vol. 58, June 1950, pages 48-52. 

